WEDNESDAY, July 20 (HealthDayNews) -- Heart patients who may have one of the estimated 28,000 Guidant Corp. pacemakers that are at risk of failing should consult with their doctor to see if they need a replacement, health experts are advising.

On Monday, the company alerted doctors that nine older models of its pacemakers have a defect that could cause them to malfunction, possibly resulting in death, particularly for patients who depend on their pacemaker to keep their heart beating. For these people, the pacemaker should be replaced, the company said.

"The decision whether to replace these pacemakers is made between the physician and the patient, based on that patient's medical situation," said Guidant spokeswoman Annette Ruzicka. "We are advising physicians to evaluate each of their patients who may have one of these affected devices to determine if replacement is necessary."

One heart expert agreed the problem is potentially serious, especially for "pacemaker-dependent" patients whose pacemaker keeps them from having no heartbeat.

"This is a fairly unusual problem," said Dr. Anne Curtis, president of the Heart Rhythm Society and chief of cardiology at the University of South Florida. "It sounds like for pacemaker-dependent patients, it could be meaningful, and they should be advised to have their pacemakers replaced."

"But for the majority of patients with these pacemakers, the answer is going to be to leave it alone," Curtis added. "If a patient is not sure if they have one of these pacemakers, they should contact their physician. If it is one of these devices, then their doctor can check the device to see if it's still working properly and discuss the risk and what should be done."

A pacemaker is a small, battery-operated device that helps the heart beat regularly. According to the American Heart Association, most pacemakers are "demand pacemakers" that have a sensing mechanism. It turns electronic signals to the heart off when the heartbeat is above a certain level, and turns the signal back on when the heartbeat is too slow.

Monday's alert affects some 28,000 pacemakers made from 1997 to 2000 that are still implanted in patients worldwide, including 18,000 in the United States. According to Guidant, a component used to seal the pacemakers could fail, allowing moisture to build up and causing the devices to malfunction.

Of the 78,000 pacemakers sold, 69 exhibited a problem, with five patients suffering dizziness or temporary loss of consciousness. Another patient, with assorted health problems, experienced "pacing" difficulties with the device and was admitted to a hospital, where the patient later died. It's not known if the death was due to problems with the pacemaker because the device was not returned for examination, the company said.

The projected rate of failure for the implanted devices appears to be between 0.17 percent and 0.51 percent for the remaining life of the pacemaker. The devices have a lifespan that can range from seven to 10 years, the company said.

The devices affected are: PULSAR MAX, PULSAR DISCOVERY, MERIDIAN, PULSAR MAX II, DISCOVERY II, VIRTUS, PLUS II, INTELIS II and the CONTAK TR, according to the U.S. Food and Drug Administration

Guidant's Ruzicka said the company would cover the cost of a new pacemaker, plus $2,500 in any additional costs for replacement surgery beyond what Medicare or other health insurance would pay.

Another heart expert thinks the pacemaker problem can be handled without causing further problems to patients.

"This is a problem we can get our hands around," said Dr. Eric N. Prystowsky, a cardiologist at St. Vincent Medical Center in Indianapolis, and a member of Guidant's medical advisory board. It is an important problem, he noted, because if you have a pacemaker that is keeping you from having no heartbeat, a malfunction can result in death. "With this patient, you can't take a chance and you simply have to replace the unit," he said.

However, Prystowsky added that if the pacemaker was implanted to deal with other intermittent heart problems, such as a slow heart beat, he would not replace the device, but only replace it when it reached the end of its battery life.

"If a patient has a pacemaker, they know what pacemaker they have," Prystowsky said. "If you have a pacemaker and it's not a Guidant pacemaker, just keep your routine follow-up with your physician. This doesn't concern you."

And if you "have a pacemaker that was put in within the last year, this recall doesn't pertain" to you, he added.

The Heart Rhythm Society's Curtis noted that problems with heart devices in general happen from time to time, and with all companies that manufacture them. "The number of advisories that we have heard from Guidant over the past two months have been unusual, but there isn't a company out there that at some time hasn't occasionally had an issue," she said.

Sales of pacemakers account for $1.8 billion, or 47 percent, of Guidant's total annual sales, the company said. Guidant has about one-third of the pacemaker market in the United States. Other pacemaker manufacturers include St. Jude Medical Inc. and Medtronic.

The pacemaker alert is the latest headache for Indianapolis-based Guidant. In June, it recalled an estimated 109,000 implantable defibrillators due to malfunctions that may have resulted in two deaths, according to the FDA.

One heart expert doesn't think Guidant's current problems will affect whether doctors will choose its products.

"There is a lot of concern about the recalls in the last couple of months," said Dr. Jeffrey Goldberger, director of cardiac electrophysiology at the Bluhm Cardiovascular Institute of Northwestern Memorial Hospital in Chicago.

"My personal view is that you have to look at the industry over a long period of time," Goldberger said. "All the manufacturers have had recalls, issues and problems. I would not say this would have a long-term impact on the choice of devices. In the short-term, people may want to wait and see what happens."

More information

The Guidant Corporation can tell you more about the advisory on their pacemakers and implantable defibrillators.